Ladder construction



NOV- 27, 1945. D. s.` sAMPsoN LADDER CONSTRUCTION Filed 0st, 24.y 1944 Dona/d S. Sampson@ Patented Nov. 27, 1945 the constructions, tions herein described and claimed.-

UNITED STATES PATENT OFFICE LADDER CONSTRUCTION Donald S. Sampson, Silver Spring, Md.

Application October 24, 1944, Serial No. 560,127

5 Claims.

This invention relates to'ladders and more parcularly to extension ladders and it consists in arrangements and combina- Extension ladders so Tar available are of a very eavy' and cumbersome contraction, requiring a great deal oi skill as well as strength to position the ladder in an operative working position and also requiring an equal exertion to lower the ladder from such position. In addition, such ladders require considerable space for storage purposes, and due to the above difculties the average householder is discouraged in the use of such ladders.

It is therefore the cardinal purpose of the invention to present an extension ladder which may be constructed from light weight metals, providing ready portability, stituting the ladder for the purpose of storage in a limited space.

and in which the parts conmay be quickly dismantled More specifically, it is an object of the invention to provide a ladder in which the upright or stile members are erative relation members, the rung members and the stile memmaintained in their spaced opby means of detachable rung bers being constructed to interlock in a manner to aiord'stability and rigidity to the ladder; as well as providing an end to end interconnection between two or more ladder sections, in a novel manner.

30 Additional objects, advantages and features of -invention will be apparent from the following description considered in conjunction with the accompanying drawing, wherein ladder illustrating Figure 1 is a front elevation of a portion of the invention, Figure 2 is a fragmentary perspective view illustrating the juncture of a pair of overlapped stile members.

Figure 3 is a fragmentary perspective view of a 40 modied form of connection for the stile members and also illustrating the detachable mounting of the rungs.

Figure 4 is an outside elevation thereof,

Figure 5 is a vertical section on the line 5-5 of 45 Figure 4,

Figure 6 is a cross section on the line 6-6 of Figure 5.

the rungs.

Figure 8 is a cross sectionon the line 8-8 of Figure 5.

Figure 9 is a front elevation of a portion of one of the Stiles.

Attention is rst invited to Figure 1 of the 55 (Cl. 22S- 57) drawing, wherein there is illustrated a portion of a ladder generally indicated by the reference character I0, consisting of a pair of stiles or uprights I I connecetd in spaced relation by detachable rungs I2 as will be described. The stiles II may be of any suitable lengths and the rungs I2 will be spaced apart as in conventional extension ladders.A Y

It is contemplated to formthe stiles and rungs from aluminum, magnesium and alloys thereof, or similar metals, since these have been found to be extremely light in weight, of great strength, and affording rigidity to the ladder when so constructed.

Each of the stiles II are of identical construction, consisting of longitudinal flat strips oi metal of a suitable thickness, and'spaced longitudinally thereof key-hole slots I3 are formecLthese slots being positioned in the medial longitudinal axis of the strips, and at the same distance apart, so that when the stiles are arranged in parallel relation, the slots of one stile will be aligned with slots of the other stile. With the Slots thus aligned, the rungs I2 may be readily inserted in aligned pairs of slots and thus secure the stiles in.

As may be seen in Figure 9, are formed with a flat base Y vertical walls II, of a-height the same asthat of the thickness of the rung I2. continued convergently inward, as at I8, and terminating in a vertical slot I9. The distance between the base I6 and the termination of the slot I9 is such as to readily admit a rung edgewise therethrough, the divergent walls i8 providing ample clearance so that the `rung may be rotated slightly to present the hat side snugly upon the base I6, with the sides of the kerfs I d snugly seated upon the opposite sides of the stock, forming the stile. It will be seen from Figure 6 that the kerfs I4 present shoulder portions 20 which firmly engage the stile, thus preventing loose movement between the rungs and Stiles.

A ladder constructed as described may be employed as a single section where low heights are involved, but where a ladder of greater length is desired, additional sections may be quickly and I 6, opposed parallel the keynoie `slots is The walls I1 arel .easily secured thereto, as will now be' explained.

Each of the stile members Il is formed with a keyhole slot I3 for the topmost rung, as may be seen in Figure 2, and the stiles of the extension ladder section lil will also include a keyhole slot I3 for support of the lowermost rung of the ladder. The stiles are each formed with openings aligned with the keyhole slots, for a purpose to be explained.

As shown in Figures 1 and 2, the stiles I l of the extension section I are disposed upon the outer faces of the stiles Il of the ladder l0 in parallel overlapped relation. With the openings and keyhole slots aligned bolts 2l are inserted through the openings and secured by a nut 22. The rung is next inserted and moved into interlocked engagement with the overlapped Stiles. Inasmuch as the overlapped stiles present a double thickness of metal the kerf of the connecting rung must be wide enough to accommodate the increased thickness, as exemplied in Figure 8.

The modified form of ladder illustrated in Figures 3 to 8 embodies the identical construction of keyhole and rung, the only material diierence being in the shape of the stile members. In these iigures the stiles are formed as channel members indicated at 23, the stiles of the upper section being nested within the channel of the lower section. The same reference characters are ernployed to designate the corresponding parts of Figures 1, 2, and 9. In the form shown in Figures l and 2, the bolts 2l carry the load of the upper section, and in order to lessen the load thereon an outwardly pressed lug 24 is formed upon the upper channel member 23, positioned so as to rest upon the upper edge of the stile of the lower channel member 23. The lower channel member is also provided wit-h a lug 24 but in this instance the lug is pressed inwardly so as to lie in the path and engage the lower end of the upper channel.

A ladder constructed and assembled as described, it will be seen can be readily dismantled, by grasping a rung intermediate of its length and giving it a partial rotation so as to present a longitudinal edge within the slot I9 of the keyhole, permitting ready removal of the rung. When all rungs have been removed, the stiles will be in a separated state and all parts may then be stacked in a bundle and tied, for safe storage. Of course, in case the extension section is employed, it will be necessary to remove the bolts and nuts to separate the stile sections.

While I have shown and described preferred forms of the invention, this is by way of illustration only, and I consider as my vown all such modications as fairly fall within the scope of the appended claims.

I claim:

1. An extension ladder comprising, a pair of parallel stile members having longitudinally spaced keyhole slots, each slot having a flat base, a pair of opposed vertical walls defining respective terminal ends of the base, and a longitudinally extended slot, the slots of one stile member being in horizontal alignment with the slots of the other stile member and a flat rung member insertable edgewise through said keyhole slots, each of said rungs having opposed kerfs at the ends of a width and depth to snugly contact said vertica1 walls of the keyhole slots when partially rotated and brought to rest upon the flat base of the keyhole slots. Y

2. An extension ladder comprising a pair of overlapped stile members detachably connected in end to end relation, longitudinally spaced keyhole slots formed in said Stiles, the slots of the stiles at the overlapped portions being in alignment and a flat rung member insertable through aligned keyhole slots, each rung having opposed kerfs at the ends of a width and depth to snugly contact edges of the keyhole slots when said rungs are partially rotated and brought to rest upon the base of said keyhole slots.

3. In an extension ladder, a pair of stile members, each stile member consisting of overlapped sections detachably connected together, each stile member having longitudinally spaced keyhole slots, the slots of one stile member being in horizontal alignment with the slots of the other stile member, one series of slots being formed at said overlapped portions and a rung member detachably connected between each pair of aligned slots.

4. In an extension ladder, a. pair of stile members, each stile member consisting of elongated sections arranged in end to end overlapped relation, each stile member having longitudinally spaced keyhole slots, each slot having a flat base, a pair of opposed vertical walls and a longitudinally extended slot, the slots of one stile member being in horizontal alignment with the slots of the other stile member, one series of slots being formed at said overlapped portion and a flat rung member insertable atwise through said keyhole slots, the rungs having opposed kerfs at the ends of a width and depth to snugly contact said vertical walls of the keyhole when partially rotated and brought to rest upon the flat base of the keyhole slots.

5. The structure of claim 4, in which the elongated sections are channel members telescoped one within the other, each channel having a lug for mutual endwise support of the other.

DONALD S. SAMPSON. 

